The present invention relates generally to valve systems and injector systems including such valve systems and, particularly, to valve systems for use in injecting multiple fluids and to injectors systems including such valve systems.
In many medical procedures, such as drug delivery, it is desirable to inject a fluid into a patient. Likewise, numerous types of contrast media (often referred to simply as contrast) are injected into a patient for many diagnostic and therapeutic imaging procedures. For example, contrast media are used in diagnostic procedures such as X-ray procedures (including, for example, angiography, venography and urography), computed tomography (CT) scanning, magnetic resonance imaging (MRI), and ultrasonic imaging. Contrast media are also used during therapeutic procedures, including, for example, angioplasty and other interventional radiological procedures. Regardless of the type of procedure, any fluid injected into the patient must be sterile and contain a minimum of pyrogens.
A number of injector-actuated syringes and powered injectors for use in medical procedures such as angiography, computed tomography, ultrasound and NMR/MRI have been developed. U.S. Pat. No. 4,006,736, for example, discloses an injector and syringe for injecting fluid into the vascular system of a human being or an animal. Typically, such injectors comprise drive members such as pistons that connect to a syringe plunger. For example, U.S. Pat. No. 4,677,980, the disclosure of which is incorporated herein by reference, discloses an angiographic injector and syringe wherein the drive member of the injector can be connected to, or disconnected from, the syringe plunger at any point along the travel path of the plunger via a releasable mechanism. A front-loading syringe and injector system is also disclosed in U.S. Pat. No. 5,383,858, the disclosure of which is incorporated herein by reference.
As illustrated in FIG. 1, in several currently available injector systems (see, for example, U.S. Pat. No. 5,494,036 and Published U.S. Patent Application No. US 2004-0064041) an injector 10 includes two syringe interfaces 20a and 20b to which two syringes 50a and 50b are removably attachable. Injector 10 includes two drive members or pistons 30a and 30b which are operable to drive plungers 60a and 60b to pressurize fluid within the syringes so that two different fluids can be injected sequentially or simultaneously. For example, syringe 50a can contain a contrast medium and syringe 50b can contain a diluent or other medical fluid such as saline. As illustrated in FIG. 1, a T-connector 70 is typically provided to connect the fluid paths from each of syringes 50a and 50b to a fluid path connected to the patient. Check valves 80a and 80b can be provided to ensure that fluid cannot flow into either of syringe 50a and syringe 50b, respectively, via the fluid set attached to the syringes. As an alternative to a T-connector, a stopcock can be provided with check valves as described above. Unfortunately, these configurations add cost and only address parts of a needed device for these types of power injection systems. For example, a check valve provides directional flow to prevent backflow; however it does not provide the ability to perform a patency check. In a patency check, the plunger of one of the syringes in fluid connection with the patient is drawn rearward to check if blood is drawn into the fluid path. Drawing blood into the fluid path provides an indication that a catheter on the end of the patient fluid path is appropriately within a blood vessel.
It is desirable to develop improved devices, systems and method for use in connection with injector systems to reduce or eliminate the above and other problems associated with current injection systems while keeping cost of goods in check